384 INTERNAL SECRETION 



In pubertas prascox, the acceleration of growth is accom- 

 panied by premature ossification and closing of the epiphysal 

 synarthroses (Neurath). In chlorosis, precocity is said to be 

 expressed by shortness of the legs and premature disappearance 

 of the epiphysal synarthroses (Tandler). 



A certain amount of evidence is also forthcoming concerning 

 the effect upon growth of the administration of extracts of the 

 genital glands. 



Lowy showed that the skeletal pecularities described by 

 Sellheim are not observed if young capons are given testicular 

 substance, and that a premature arrest of skeletal growth may be 

 obtained in young hens by feeding them with ovarian substance. 

 Dor and Maisonave, Parhon and Antoniu, and Monziols describe 

 inhibition of bony growth after the subcutaneous injection of 

 testicular extract. 



These observations all prove that there is an intimate relation- 

 ship between the development of the skeleton and the internal 

 secretory activity of the genital glands. In order to arrive at a 

 fuller understanding of this relationship, it must be borne in 

 mind that the increased skeletal growth is a secondary result, due 

 to the imperfect ossification of the epiphysal synarthroses ; this 

 fact suggests that the genital glands elaborate a hormone which 

 stimulates the processes of ossification. 



The interrelationships which subsist between the genital 

 glands and those other internal secretory organs which are known 

 to influence the growth of the bones, are also very remarkable. 

 This nexus finds expression in the fact that castration is followed 

 by changes in the thyroid, thymus, and hypophysis ; and that, 

 further, the removal of the latter organs produces alteration in 

 the structure of the genital glands. 



In a eunuch dissected by Tandler and Gross, the thyroid 

 apparatus was found to be remarkably small (weight 13 grm. as 

 against 45.8 grm. in normal persons) while thymus-persistency, 

 so frequently observed in animals after castration (Calzolari, 

 Henderson, Noel Paton), was observed in this instance also. By 

 means of skiagrams of living scopts these authors further dis- 

 covered hypophysal enlargement, their results being confirmed 

 by the fact that in the eunuch which they dissected there was 

 increase in the length, breadth, and depth of the sella turcica. 



That the removal of the genital glands is associated with an 

 increase in the size of the hypophysis was first shown in the case 

 of animals by Fichera (1906), who succeeded in rapidly reducing 

 this enlargement by the injection of testicular extract. 



It is very difficult to estimate the extent to which the skeleton 

 is directly influenced by the genital glands, owing to the fact 

 that the thymus, thyroid, and hypophysis all affect the growth of 

 the bones, their combined influence being extremely complicated, 

 in part antagonistic, and in part co-operative. 



The same applies to the influence of the genital glands upon 



